Trigger sprayers are well-known in the art. Trigger sprayers utilize a handheld reservoir, typically depending from a manual pump. The reservoir may hold any liquid desired to be sprayed in a stream, fine droplets, foam or mist. The liquid may comprise an air freshener, fabric refresher, hair spray, cleanser, etc.
The pump is activated by an articulating trigger. The user squeezes the trigger with his or her hand, typically retracting the trigger from a forward resting position to a rearward dispensing position. The motion of the trigger causes pumping of the liquid from the reservoir and ultimate spraying thereof.
The characteristics of the spray, e.g. stream, droplets, mist, are determined by several parameters and operating characteristics of the pump. For example, the nozzle geometry, piston bore, piston stroke and pump efficiency will all affect the spray characteristics.
The situation is complicated if a pump designed for one particular liquid is used with a different liquid. The liquid rheology, surface tension, etc. also affect the spray characteristics.
The situation is further complicated by user operation. The pump may be designed and intended to be used with full trigger strokes, each stroke dispensing a full volume of the piston displacement at a particular stroke speed. However, the user may not always, or ever, operate the trigger in the intended manner.
If the piston bore is too large, the force necessary to achieve proper trigger stroke may be too great for a particular user. If the piston stroke is too long or if the trigger articulation is too long, the user may not pull the trigger for the entire intended path length. If the user's hand is too small or too large, the user may not operate the trigger as intended. The user may operate the trigger slower or faster than intended. The user's hand may fatigue and operation may change in the middle of a particular usage and even mid-stroke.
Thus, there is a need in the art to accommodate not only intended use conditions for a particular liquid, but real-world conditions as well.
U.S. Pat. No. 3,768,734 to Anderson Jr. et. al. (Arrowhead Products); U.S. Pat. No. 4,503,998 to Martin (Universal dispensing Systems); U.S. Pat. No. 4,691,849 to Tada; U.S. Pat. No. 4,819,835 to Tasaki (Yoshino); U.S. Pat. No. 4,940,186 to Tada; U.S. Pat. No. 5,156,304 to Battegazzore (Guala) teaching a spraying device having a rocker lever for converting angular trigger motion to pump displacement; U.S. Pat. No. 5,299,717 to Geier (CoCoster Tecnologie Speciali) teaching a manual spray device having the axis of the piston generally parallel to the motion of the trigger; U.S. Pat. No. 5,318,206 to Maas et al. (AFA Products); U.S. Pat. No. 5,385,302 to Foster et al. (Contico Int'l) teaching a trigger sprayer having a pump assembly parallel to the discharge path; U.S. Pat. No. 5,570,840 to Gettinger (Fourth and Long) teaching a spraying device having first and second pumps; U.S. Pat. No. 5,575,407 Foster et al. (Contico Int'l); U.S. Pat. No. 5,593,093 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,645,221 to Foster (Contico Int'l); U.S. Pat. No. 5,628,434 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,628,461 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,884,845 to Nelson (Continental Sprayers) U.S. Pat. No. 6,244,473 to Keung et al. (Owens Illinois Closure); 2009/0008415 A1 to Ohshima (Mitani Valve); Re. 35,744, reissued Mar. 17, 1998 of U.S. Pat. No. 5,234,166 to Foster et al. (Contico Intl); U.S. Pat. No. 5,228,602 to Maas et al. (AFA Products); U.S. Pat. No. 5,341,965 to Maas et al. (AFA Products); U.S. Pat. No. 5,425,482 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,467,900 to Maas et al. (AFA Products); U.S. Pat. No. 5,507,437 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,509,608 Reexamination Certificate B1 (4195) to Foster et al. (Continental Sprayers); U.S. Pat. No. 5,513,800 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,549,249 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,551,636 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,553,752, Reexamination Certificate C1 (4343), to Foster et al. (Contico et al); U.S. Pat. No. 5,566,885 to Foster et al. (Contico Int'l); U.S. Pat. No. 5,615,835 to Nelson (Contico Int'l); U.S. Pat. No. 5,730,335 issued to Maas et al. (AFA products); U.S. Pat. No. 5,984,149 to Thanisch et al. (Spraysol); U.S. Pat. No. 6,116,472 to Wanbaugh et al. (Calimar); U.S. Pat. No. 6,131,820 to Dodd (Calimar); U.S. Pat. No. 6,234,361 to Bloom (Owens Illinois Closure) U.S. Pat. No. 6,364,175 to Bloom (Owens Illinois Closure); U.S. Pat. No. 6,378,786 to Beeston et al. (Reckitt Benkiser); U.S. Pat. No. 6,425,501 to Keung et al. (Owens Illinois Closure); U.S. Pat. No. 6,910,605 to Schuckmann et al. (Schuckmann); U.S. Pat. No. 7,017,833 to Foster (Continental AFA Dispensing); U.S. Pat. No. 7,175,056 to Buti (Spray Plast); U.S. Pat. No. 7,219,848 to Sweeton (Meadwestvaco Calimar); U.S. Pat. No. 7,413,134 to Tsuchida (Yoshino Kogyosho); U.S. Pat. No. 7,410,079 to Kuwahara et al. (Yoshino Kogyosho); U.S. Pat. No. 7,467,752 to Sweeton (Meadwestvaco Calimar); U.S. Pat. No. 7,497,358 to Clynes et al. (Meadwestvaco Calimar); EP 7 757 984; WO 2009/078303; JP 2003-230854; EP 1317963; JP 2503986; and JP 2003-200087 show various attempts in the art.